Hi Guys,

My car is just under 6 months old, It is a sentra running the SR20DE Engine. It done 16000 KM's so far.

The only changes that were made to the car was an air filter and exhaust change, otherwise the car is stock standard.
I have never entered a drag race before and will be entering my first one tomorrow. I have done normal street racing and freeway racing one on one, but nothing that has been timed and a pressure situation. It has all been done for fun.

I didn't modify the timing yet, cos I am not allowed to so soon cos of the warranty on the car. I will be using Shell 97 Octane fuel (that's the only fuel that I fill up with everytime). The tyres are 195/55/15's Continentals.

Is there any advice that you can give this first timer for the drag race. How hard do you think I should push the car, or at what rev should I try lauch to get the best take off and speed. I don't know that the conditions on the tracks are except that it will be a warm day and the track is an air-port strip.

I would like to see what power this car has as stock standard and what potential it can have once the mod's are to start happening. From where I am, I was told by many people that these engines are one of the best 2 litre engines out and give someone a hard time racing.

There are some fast Sentra's that I know of and apparently one of them that outrun's BMW's M3 and possibly the M5 in all departments, take off and top end. Whether this is true or not, I can't verify cos I really don't know how powerful these engines are. I have seen what changes can be made to it though (on the SE-R Website)

PS. Other mods will happen as I get some cash and the mods are approved by the dealership that I purchased the car from. The first mods that I will probably make are the CAI and then the CHIP.

Okay, back to the original reason of this post. Advice please.

Thank you in advance.

Hi
did you advance your timing?
17-19?????'
if not do it.

Lower your front tire pressure for more traction, and be carefull about getting wheelhop, *** that will crack your tranny. Keep the Engine cool in between runs.

do NOT lower your airpressure in your tires.. This does absolutely nothing for street radials.. they are not wrinkle walls.. all you will be doing by lowering your airpressure is creating more rolling resistance and probably slowing yourself down.. I run faster times with 33psi in my tires than with 20psi..also set your rear tires to the max air pressure on the tire.. this creates less rolling resistance in the rear

1. bump your timing. its a harmless 2* advance... it wont kill your engine so wont void warranty

2. lowering tire pressure = larger contact patch = more traction available.

i went to the track with my stock sentra and did a variety of launch rpm + tire pressure.

i dropped the pressure and kicked the rpm ups... the best was having pressure at ~22psi (warm) and launching from 5500rpm.

i didnt drop the clutch or feather it any.. the clutch is kinda old... so that if i just let it up kidna quickly... itll bite just enough to get the car out of the hole without too much wheelspin/hop.


for your new car i think you should experiment around 4500/5000rpm and slip the clutch a bit...

This is true, often stated by Tim the tire man with the tire mans tip of the day. Lowering your tire pressure in street radials does nothing but create drag make you use more gas, it does nothing for traction, these are not slicks. A common misconception even around here it appears.

Originally posted by sr20ser1997
do NOT lower your airpressure in your tires.. This does absolutely nothing for street radials.. they are not wrinkle walls.. all you will be doing by lowering your airpressure is creating more rolling resistance and probably slowing yourself down.. I run faster times with 33psi in my tires than with 20psi..also set your rear tires to the max air pressure on the tire.. this creates less rolling resistance in the rear

sorry i have to disagree with you. I can DEFINITELY tell a difference when lowering the pressure on my front tires, even on the street. Dont drop it TOO low, but goin down to just below 30 WILL help. Test it out and practice to see what works best for you. It really depends on your car / tire set up. Limited slip is right ***, anywhere in the 4000-5500 range should get your a good launch assuming u can control the spinning. Good luck.

Originally posted by PlanoSER
sorry i have to disagree with you. I can DEFINITELY tell a difference when lowering the pressure on my front tires, even on the street.

Honestly how can you tell the difference, your 1/4 mile times are a few 10ths off? Especially on the street? The fact remains to be true all it does is give you less gas mileage, and does not improve traction the slitests. This may be a poor analogy but when you get a flat tire does your traction increase or decrease. Also if your tire pressure is lower on one side it will pull to that side why? Cause it's creating drag.

PSH...

Honestly how can you tell the difference, your 1/4 mile times are a few 10ths off?

Ive heard from many respectable people that lowering your tire pressures will better 60ft times.

The fact remains to be true all it does is give you less gas mileage,

your worried about gas mileage while redlining down a quarter mile????

This may be a poor analogy but when you get a flat tire does your traction increase or decrease. Also if your tire pressure is lower on one side it will pull to that side why? Cause it's creating drag.

Finally , we agree... That is a poor analogy

When my car was stock I lowered my pressure to 22psi and still got wooped by a corvette. :confused:

I think I would do it just for mental kick.

your worried about gas mileage while redlining down a quarter mile????

No, not at all, mearly stating the reason you get poor gas mileage is because you have more drag. If you believe lowering your tirepressure on street radials gives you better traction, then by all means continue with it. But if you do a little research you will find out otherwise. just FYI

your acting like im recommending lowering pressures while driving on the street. I sure hope you dont think that is what im referring to. On the street you want a pressure that allows for proper tire wear. Its a well known fact that increased tire pressures help for grip ( i.e. autocross ). Lowering pressures in the front *should* allow for a larger contact patch. Great for drag racing. Period

Originally posted by Black93
Lowering pressures in the front *should* allow for a larger contact patch. Great for drag racing. Period
actually i beg to differ.. if you over inflate you tires you wear the middle down because the sides of the tires are not contacting the road as much as the center of the tire.. however if you deflate the tire you will be wearing out the edges of the tire..this being because the center of the tire is not contacting the road as much as the edges.. the tire almost forms a "n" shape as its contacting the road on an underinflated tire.. your best bet is to keep your front tire at the car manufactures recommended inflation for the front.. lowering your tire pressure on a street radial is pointless. PERIOD

Iknow this is off the subject, but what does a sentra from south africa look like? just wondering...... From my ex. lowering the pressure more than 6-7 psi doesn't help much. I run 33 psi on the street. LOL:)

BTW, Yes I know you are not recommending lowering tire pressure for street use, this is a track only discussion.:cool:

if you over inflate you tires you wear the middle down because the sides of the tires are not contacting the road as much as the center of the tire.. however if you deflate the tire you will be wearing out the edges of the tire..

Dont overstate the obvious, this is true for street purposes. IM referring to motorsport purposes. Next time you autocross you use the manufacture's recommended pressures. I shouldnt have any troubles bettering your time by say a good 10 seconds.

lowering your tire pressure on a street radial is pointless. PERIOD

taken from SE-R.net under "SE-R Drag Tips"...

5. Tire pressure. It's good to lower the pressure a bit on the front tires. This gives bit wider track, and the "spongeyness" of the lower pressure seems gives a bit more grip. I lower my Yokohama A509s (185/60/14) to about 25 psi. You can also pump up your rear tires by a few psi for less rolling resistance.


Games over,
Nathan has finished zipping the flame suit.

Originally posted by Black93
taken from SE-R.net under "SE-R Drag Tips"...

5. Tire pressure. It's good to lower the pressure a bit on the front tires. This gives bit wider track, and the "spongeyness" of the lower pressure seems gives a bit more grip. I lower my Yokohama A509s (185/60/14) to about 25 psi. You can also pump up your rear tires by a few psi for less rolling resistance.

Games over,
Nathan has finished zipping the flame suit. [/B]

You think because it is written on there that it is law? Half the stuff on that site is so out of date it is rediculous, and that is one mans opinion not fact. We are stating facts not opinions.

I know, from my experience racing at the track and on the street, that I get better launches and times by dropping the front tire pressure.

With "recommended" PSi, i got a shitload of wheelspin and wheel hop... Once i lowered the tire pressure, I got NO wheelhop and hardly any wheelspin, my 60ft times were consistently lower, and my ET's were in turn lower.

This is just my experience. I dont care if it goes against anything you think or "know" :rolleyes:

Originally posted by sr20ser1997

lowering your tire pressure on a street radial is pointless. PERIOD

I strongly disagree.

Lowering the pressure (in most street tires) creates a softer sidewall, which is less prone to wheelhop, and for me, a better launch.

Dan
14.6 @ 94, all motor, unstripped, on street tires @ 20 psi

Lowering the pressure in my street radials help me reduce my 60ft. times, as well as overall 1/4 mile time.